[Abdullah]

You need an antifungal too.

[Abdullah]

@vitalys what about Stratum Corneum? Does it have water? Because this is the outermost layer and what will be in contact with cosmetic products.

[Abdullah]

@chemicalmatt thanks

For me 1% SPDMA needed 5% lactic acid that supplier said is 80%. That is very big difference.

Does it mean this lactic acid is not really 80% and supplier is lying? 

Supplier is a wholesaler, not manufacturer and i purchase salicylic acid & citric acid from them too. They have good quality. 

Is there any way to check if this lactic solution really has 80% lactic acid or not? 

[Abdullah]

@ketchito thanks 
I use only 0.5% cationic surfactant+ fatty alcohol in emulsion. 
People who has used these cationic emulsions all liked it more than emulsions with these anionic & non-ionic surfactants (GMS, sodium stearoyl lactylate, polyglyceryl-4 laurate) stabilized with xanthan gum. Do you think 0.5% BTMS or BTMC will cause irritation?

For me cationic emulsion has a lot of advantages and most importantly somehow the final product costs less than emulsion with very inexpensive anionic & non-ionic emulsifiers mentioned above. 

[Abdullah]

Fekher said:

@Abdullah nice subject to treat and as short answer I guess it should be above 4.8
https://www.paulaschoice.com/expert-advice/skincare-advice/skin-care-myths/the-ultimate-guide-to-ph-and-your-skin.html

Thanks

[Abdullah]

Try 10:1 ratio.

[Abdullah]

How much is the profit margin? 

If the profit margin is too low, you will not make enough profit to make you motivated enough to sell more. 

[Abdullah]

@ketchito i use 80% lactic acid solution that has 80% lactic acid solids & 20% water. By solid i mean actual lactic acid. 

Do you also need 4.5% lactic acid 88% solution to neutralize 1% SPDMA to pH 4-4.5?

[Abdullah]

What percentage and ratio have you tried?

[Abdullah]

A chemist here once told me that skin and hair doesn’t have pH. The have isoelectric point.
Skin isoelectric point is ~4.8 
Hair isoelectric point is ~3.6

These papers all say skin pH is this and that. 

Maybe i haven’t understood it correctly so i am asking it once again. 

does skin have pH?

[Abdullah]

Does 10 ppm formaldehyde do any benefit if combined with phenoxyethanol in emulsion or CMI MI in cleansing product or this amount is useless as preservative?

[Abdullah]

PhilGeis said:

Sorry - my comment was confusing - parabens/EDTA WITH chloromethylisothiazolinone.
Parabens./EDTA alone is not - but good addition to chloromethyl isothiazolinone that is excellent vs bacteria, esp. Gram negatives.

Thanks a lot

[Abdullah]

@ketchito how much lactic acid solid do you use to neutralize 1% SPDMA? 

[Abdullah]

Agree with Jemolian & Mayday. 0.05% xanthan or 0.3% surfactant helps spreading of water much better. 

[Abdullah]

What is the preservative and surfactant?

[Abdullah]

@PhilGeis please correct me.
Paraben is antifungal and weakest against gram negative bacteria and Shampoo is most susceptible to gram negative bacteria. So how is Paraben a good option for shampoo? 

[Abdullah]

Thanks

[Abdullah]

@vitalys thanks a lot. 

I wasn’t available for some days. 

[Abdullah]

I dont know about the hold of HEC much. I have just experienced that xanthan gum, guar gum or flax seed gel doesn’t feel good on hair. 

Xanthan/guar ratio i gave you was just for viscosity purpose.

[Abdullah]

In my experience xanthan gum/guar gum 2/8 provide maximum viscosity.

Why don’t you use a conditioner in your hair? 
Or whay don’t you use HEC in this product? 
HEC feels much better than xanthan or guar gum in hair.

[Abdullah]

I think 25% Ceteareth 25 will make your hair dry by emulsifying any lipids that is there. Have you used this product? 

[Abdullah]

Do you mean salicylic acid?

If you are using only oil it will not have pH.

[Abdullah]

Be aware that benzyl alcohol is not more natural than phenoxyethanol or Paraben. 

Also it is ranked lower in all these aspects compared to those preservatives that you don’t want to use.
preservation effectiveness, stability of preservative it self, emulsion stability, effect on viscosity, smell and mildness to skin. 

It is recommended because there isn’t much more options left. 

[Abdullah]

My top suggestion would be Benzostat if you want to use only one preservative and not use those that you have listed. 

It is
71% benzyl alcohol

15% caprylhydroxamic acid
14% glycerin

[Abdullah]

Also there isn’t one preservative or blend that is good for both emulsions and shampoos except DMDM hydantoin. 
There will be side effects like reduced viscosity, reduced activity, unnecessary high cost, irritation and so.

I suggest you have two combinations. One for cleansing products. One for leave on products.